The present invention relates to an ink fountain apparatus for a rotary printing press, which stores ink to be supplied to a plate surface and, more particularly, to the structure of intermediate ink dams arranged between a pair of opposing ink dams.
When printing is to be performed with a rotary printing press, the plate sometimes has a pattern at only its portion in the entire width depending on the specifications of the printing products to be obtained. In this case, if ink is stored in the entire ink fountain and printing is performed, the ink may be wasted. Hence, intermediate ink dams are formed on two sides of a portion corresponding to the pattern, and the ink is stored in only inside the intermediate ink dams. In rainbow printing wherein inks of different colors are supplied to appropriate portions in the entire length of the plate cylinder and several colors are printed at once, intermediate ink dams are provided so adjacent inks do not mix with each other. Japanese Utility Model Publication No. 6-46675 (reference 1) discloses an ink fountain apparatus of this type.
The ink fountain apparatus shown in reference 1 has an intermediate ink dam unit, movable in the axial direction, on a holder shaft extending parallel to an ink fountain roller. The intermediate ink dam unit has a holder fitted on the holder shaft, a support plate pivotally supported by the holder through a link, an intermediate ink dam fixed to the support plate and made of an elastic material, a spring for pressing the edge of the intermediate ink dam to abut against a blade, and a pivoting force application member for applying a pivoting force to the holder in a direction to press the intermediate ink dam to abut against the outer surface of the fountain roller.
In this arrangement, because of cooperation with the elastic force of the spring member, the acting force of the pivoting force application member, and the link motion, the elastic edge of the intermediate ink dam is pressed by the outer surface of the ink fountain roller and the flat surface of the blade to abut against them, and comes into tight contact with them.
In the conventional ink fountain apparatus described above, the intermediate ink dam is brought into tight contact with the outer surface of the ink fountain roller and the blade by pivoting the whole intermediate ink dam with the pivoting force application member. In this pivot motion, although the whole intermediate ink dam can be brought into tight contact with the outer surface of the ink fountain roller and the blade, it cannot necessarily be brought into uniform contact with them due to a working tolerance, non-uniform wear, or the like. Therefore, in the conventional ink fountain apparatus, the tight contact force cannot be partially adjusted.
Accordingly, when the tight contact force of the intermediate ink dam decreases partially, the ink flows out through this portion, so the amount of ink consumed may increase, and the printing quality degrades in rainbow printing or the like. When the intermediate ink dam is to be removed, the link mechanism and the like must be removed, resulting in a cumbersome operation.
It is an object of the present invention to provide an ink fountain apparatus for a rotary printing press, in which the consumption of ink is reduced by preventing outflow of the ink.
It is another object of the present invention to provide an ink fountain apparatus for a rotary printing press, in which the printing quality in rainbow printing is improved.
It is still another object of the present invention to provide an ink fountain apparatus for a rotary printing press, in which an intermediate ink dam can be removed easily.
In order to achieve the above objects, according to the present invention, there is provided an ink fountain apparatus for a rotary printing press, comprising a rotatably supported ink fountain roller, an ink fountain comprised of a bottom plate with one end supported close to the ink fountain roller and a pair of ink dams standing upright from the bottom plate to correspond to two ends of the ink fountain roller and arranged to oppose in an axial direction of the ink fountain roller, at least one intermediate ink dam standing upright between the ink dams from the bottom plate, the intermediate ink dam including a first member in contact opposite to an outer surface of the ink fountain roller and the bottom plate, a second member in contact opposite to the first member, and a third member in contact opposite to the second member, press means for pressing the first member through the third and second members toward the outer surface of the ink fountain roller and toward the bottom plate, and an adjustment tool for adjusting a tight contact state of the first member with respect to at least one of the outer surface of the ink fountain roller and the bottom plate.